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Professionals in Epilepsy Care Symposium:Controversies and Challenges of EEG Monitoring
Washington, DC-Long-term monitoring with EEG/video has become an essential component of every comprehensive epilepsy center. Although significant advances have been made in neuroimaging techniques such as MRI, SPECT, PET, MRS as well as magnetoelectroencephalography (MEG), none of these has proven superior for the lateralization and localization of an epileptic focus prior to epileptic surgery. In addition, evidence obtained from EEG/video has been invaluable in discerning epileptic from nonepileptic events in many patients, establishing a basis for appropriate treatment.
Up until recently, many of the challenges of running an effective EEG/video unit were technical, such as insuring that video tapes were changed on time and time codes on the EEG and video matched. With continued improvement in computer technology, these time consuming and technical issues have been eliminated. State of the art EEG/video equipment now stores data on computer hard drives, eliminating video tapes altogether and the problem of time synchronization. Equipment has become more compact, improving the ease of outpatient monitoring. More sophisticated and reliable equipment has allowed for a shift of attention towards improving the patient’s experience while undergoing EEG/video. This symposium reviewed the indications and techniques for long term EEG/video monitoring of adults and children, methods and consequences of antiepileptic drug (AED) withdrawal, strategies to improve patient coping during hospitalization, and recommended safety procedures for the EEG/video monitoring unit.
Indications and Benefits of Long-Term EEG/Video Monitoring
Judy Ahn-Ewing, registered EEG technician and board member of the American Board of Registration of Electroencephalographic and Evoked Potential Technologists, explained the importance of long-term EEG/video for the purpose of diagnosis of unexplained events and the proper classification of epileptic seizures. Routine EEG, which may range from 20-60 minutes, succeeds in capturing epileptiform activity about 50-60% of the time, but epileptic seizures are rarely (2.5-7%) recorded. By contrast, monitoring allows documentation of the frequency of ictal and interictal EEG discharges, their correlation with clinical events, and lateralization and localization of the epileptogenic zone for possible epilepsy surgery. Clinical events captured by EEG/video may be stored for later analysis and can be instructive for patients and their families.
The primary nursing considerations of patients in the long-term EEG/video unit focus on patient care, safety, and patient education. However, many other issues need to be addressed, such as patient comfort and social isolation, which can be ameliorated by providing patient recreation, general activities, support and education. Education of the patient, family and support staff is also critical to ensuring successful recordings when portable EEG/video units are used outside of the inpatient unit.
Procedures for operating an epilepsy monitoring unit vary across settings, leading to variability in practices. For example, not all institutions require separate consents for admission to the hospital and admission to the long-term monitoring unit. Potential privacy issues may occur for patients in neighboring beds when portable EEG/video monitoring equipment is used. Additionally there are no generally accepted procedures to maintain patient safety during different procedures.
Ms. Ahn-Ewing also addressed some of the psychological issues that affect patients admitted for long-term EEG/video monitoring, “When the decision is made to admit someone to a monitoring unit, we’re giving them almost contradictory information, because we are asking them to have seizures. This can be confusing to the patient and disconcerting to families. This problem can be ameliorated by patient and family education.”
In addition to monitoring EEG and video, long-term monitoring units may utilize EKG and respiratory monitoring, as well as electro-oculograms, electromyography (EMG), and pulse oximetry. Provocative techniques such as hyperventilation, photic stimulation, sleep deprivation, exercise, psychological testing, AED withdrawal and induction of nonepileptic events by suggestion, placebo injection, or other techniques may also be employed. Semi-invasive electrodes such as sphenoidal and naso-pharyngeal electrodes may be necessary, and surgical candidates may require subdural strips, grids, or depth electrodes.
Staffing an epilepsy unit must take into consideration the need to respond promptly if the patient experiences a seizure in order to observe the clinical event, perform brief neuropsychological testing and ensure patient safety. Providing padded bedrails is just one way to help prevent patient injury. In addition, the integrity of the recording electrodes must be checked and any inadequacies in the data acquisition and storage process must be identified. Automatic spike detection facilitates data review and automatic seizure detection can supplement staff observations of clinical events. The EEG technician must archive important data and edit a master tape for physician review. Patients and families must be instructed on the use of the equipment, how to activate ‘pushbuttons’ or monitor any other equipment, and record events.
Challenges in Pediatric Monitoring
“Some of the toughest EEG you will ever read is because of artifact, especially in pediatric EEG,” declared Dennis J. Dlugos, MD, Head of Clinical Neurophysiology, Children’s Hospital of Philadelphia, Philadelphia, PA.
Dr. Dlugos emphasized that prolonged EEG/video can help establish the epilepsy syndrome in pediatric patients by detecting the EEG pattern of absence seizures or Lennox-Gastaut, which may be missed by routine, shorter recordings. Patient diaries are essential to identify a patient’s usual events and other behaviors of concern. Unfortunately, outpatient diaries of clinical events tend to contain either very limited or excessive information.
While intracranial recordings may be necessary for presurgical localization and lateralization, Dr. Dlugos cautioned, “These kids are at high risk for bad things to happen.” Potential problems include leaks of cerebrospinal fluid, infection, and bleeding. In order to properly manage patient pain and AED titration, patient care needs to be coordinated between the neurosurgical, neurological, and intensive care staffs. Dr. Dlugos advised, “These cases require a lot of planning and expertise. Serious consequences can occur if communication is not clear.” Therefore, there is a need for a clear chain of communication and decision-making throughout the hospitalization, as well as pre- and postoperatively.
Dr. Dlugos explored the issue of obtaining EEGs on children hospitalized in the intensive care unit who have spontaneous seizures. Appropriate after hours staffing is required for urgent EEG performance and interpretation. In a study of infants with asphyxia, those with seizures had a higher risk of severe cerebral palsy, delayed walking, microcephaly and failure to thrive, emphasizing the importance of identifying seizures in this population. Although data on the effects of treatment are incomplete, early identification and treatment of these seizures may improve outcome.
Dr. Dlugos spoke about a simplified brain wave monitoring technique, the cerebral function monitor, that is widely used outside of the U.S. Consisting of only 3 electrodes (2 active, 1 ground), the monitor compresses the EEG signal. Seizures may be identified by an ‘arch’ pattern on the tracing. Interpretations are typically performed by nonphysicians and are hampered by false positives and false negatives. Dr. Dlugos advised, “We have to be aware of the limitations of this technology. We have a long way to go before we can confidently diagnose seizures using cerebral function monitors.”
With respect to pediatric outpatient monitoring, Dr. Dlugos has had good success with 3-hour studies. “One needs to balance clinical needs with what a child and family will tolerate,” Dr. Dlugos concluded.
The Ups and Downs of AED Therapy in the Monitoring Unit
Collin Hovinga, PharmD, a neuropharmacologist at Miami Children’s Hospital Research Institute, Miami, Florida, discussed the risks of AED withdrawal in an epilepsy monitoring unit. While the goal is to record the patient’s typical seizures, possible complications include recording atypical seizures, physical injury, psychiatric side effects, withdrawal side effects, and precipitation of status epilepticus.
Dr. Hovinga presented several of his own personal recommendations: (1) For patients whose typical seizures are complex partial, rapid drug withdrawal should be avoided as it may precipitate secondarily generalized seizures; (2) Patients with mild or infrequent seizures may begin tapering their AEDs as outpatients, in order to decrease the length of hospitalization (only patients with adequate supervision are suitable for this approach); (3) AEDs with subtherapeutic levels should be removed first; (4) When patients are taking more than one AED, it may be optimal to withdraw the AED with the shortest half-life first; (5) For patients on monotherapy, AED dose should be reduced by 1/3 to 1/4 dose/day, and even more slowly for those with a risk for complications.
Dr. Hovinga emphasized that a plan should be in place to treat patients with acute withdrawal seizures, as the risk of seizure emergencies may range from 48% (Rose et al, Neurol 2003; Yen et al, Epilepsia 2001) to 61.5% (Haut et al, Epilepsia 2003). He shared his recommendations for identifying seizure emergencies including: generalized tonic clonic (GTC) seizures lasting 2 minutes or longer, more than 2 GTCs in an hour, more then 30 minutes of continual seizures, more than 2 seizures in a row, seizure clustering, or any seizure lasting longer than 5 minutes. Drug treatment in the event of a seizure emergency includes IV lorazepam, IV fosphenytoin, rectal diazepam, sublingual lorazepam, intranasal midazolam, or oral AED loading. Phenobarbital, phenytoin and valproate may be loaded intravenously. Gabapentin, levetiracetam and pregabalin may be orally loaded rapidly.
Psychiatric complications of AED withdrawal may include aggression, agitation, anxiety, depression and psychosis. AED withdrawal may also aggravate preexisting anxiety, depression or psychosis. Risk factors for psychosis include epilepsy severity, duration, low seizure frequency, multiple seizure types, history of status epilepticus, seizure clustering, left temporal and frontal seizure foci, and structural lesions. Psychosis may be classified as ictal, interictal, and postictal. Ictal psychosis may require IV AED treatment, while interictal psychosis may require neuroleptics. Postictal psychosis may require neuroleptics or resolve spontaneously. Neuroleptics to be avoided include chlorpromazine and clozapine, which have a higher risk of precipitating seizures. Physicians and staff need to monitor patients for adverse events from neuroleptic treatment and possible drug-drug interactions with AEDs and other medications.
Coping in the Monitoring Unit
Lynn Bennett Blackburn, PhD, a pediatric neuropsychologist at Children’s Hospital, St. Louis, MO, emphasized that although patients receive detailed instructions prior to an inpatient monitoring unit stay, they often arrive with unanswered questions and fears regarding a possible failure to have seizures. Patients may also have concerns regarding their comfort, confinement, privacy and family disruption.
Dr. Blackburn advised that patients should be reassured that many people stop having seizures on admission, but that there are methods for eliciting seizures such as tapering medication, sleep deprivation, exercise, and exposure to typical triggers if needed.
Many patients may not want to see video recordings of their own seizures, and may also be worried who else may see the video. Patients need to know that their privacy will be respected by staff and they will not be observed in the bathroom. Comfort issues such as itchy unwashed hair, boredom, and sleep deprivation also need to be addressed.
Burdens of hospitalization may include missed days at work, lost wages, possibility of job loss, unreimbursed hospital expenses, and employers becoming aware of the patient’s seizure disorder. Spouses may also encounter additional burdens as they take on responsibilities usually managed by the patient such as household chores and child care. When children are hospitalized, their schooling is interrupted and siblings may become jealous. “Having someone admitted to the hospital for 3-5 days is a huge impact on the family,” observed Dr. Blackburn.
She further explained that video monitoring puts the patient and family on display. Parenting techniques, private parent/child rituals and routines will be recorded. Parent child conflict may increase. It may be helpful for staff to provide parents with breaks.
Dr. Blackburn recommended the development of educational materials to supplement the initial appointment letter to the epilepsy monitoring unit stating that a video of the experience on DVD may be helpful. Questions related to patient fears and expectations should be added to the nursing intake form. Social workers and neuropsychologist intervention may help ameliorate developing psychosocial problems. Good communication between all members of the team is necessary. In addition, there should be a protocol for providing psychosocial support for those patients who leave the monitoring unit with a new diagnosis of epilepsy or a diagnosis of nonepileptic events. She concluded that more training materials for staff should be developed as well as multi-disciplinary research, systematic testing of interventions, defining patient phenotypes, and sharing what works with other centers.
Don’t Let the Monitoring Unit be a Shocking Experience-or Otherwise Hazardous to Your Health
Mary Bare, MSPH, RN, an epilepsy education consultant, emphasized the need for patient safety in the epilepsy monitoring unit. She advised that beds, cribs and floors should be padded and sharp objects such as safety pins and knitting needles avoided. Scalp or intracranial electrodes should be covered with a head wrap or cap and electrode wires wrapped and out of the way. If the patient has an IV, it should be covered to protect it in case of a seizure. Patient restraints should be employed when required. Standard cleaning procedures should be applied to scalp electrodes, cables and all other reusables and infection control policies enforced.
Ms. Bare suggested that nurses take a careful history of the patient’s typical seizures, which may prove invaluable during the hospitalization. She described one patient who ‘bear hugged’ anything near him during a seizure. Because the nurse had not obtained this history, she panicked when she found herself in the patient’s arms.
According to Ms Bare, continuous observation by trained professionals in an epilepsy monitoring unit is essential, “You absolutely need someone there 24 hours a day. Patients may pull out electrodes, have a seizure, fall out of bed, bad things can happen.”
Patients with intracranial electrodes are at increased risk for injury. She suggested that someone stay within arm’s reach of the patient at all times, even in the bathroom. “Bathrooms are potentially very dangerous places.”
Electrical safety is another concern. Cables, cords and machines must be in good repair. Electrical devices brought in by patients from home should receive an engineering check. Simultaneous tests, such as an EKG and EEG may cause problems with double grounding, resulting in patient injury. Extension cords should be avoided. Ms. Bare concluded, “Safety is everyone’s responsibility.”
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